1. Field
An aspect of the present invention relates to an energy storage system, and more particularly to an energy storage system and a method of controlling the same.
2. Description of the Related Art
Demand for a system for storing energy and efficiently utilizing the stored energy increases as problems such as environmental destruction, resource depletion, and the like occur. In addition, the relative importance of renewable energy, for example, solar energy, wind power, tidal power and/or the like, and preventing pollution generated in the production of energy continues to increase.
A energy storage system is a system for coupling a power generating system (e.g., a renewable energy generating system), a battery for storing energy, and an existing grid.
Further, the energy storage system serves to couple the power generating system and the grid to supply energy to a load.
The energy storage system uses energy to drive a power conditioning system, which is called an internal consumption energy of the energy storage system. In the related art, if the grid is at a normal state, the energy of the grid is used to provide the internal consumption energy and the energy to the load, and if the grid is at a non-steady state, such as a blackout, the energy storage system uses a battery power source provided at the energy storage system to provide the internal consumption energy and the energy to the load because the energy storage system performs an Uninterruptible Power Supply (UPS) operation.
However, since an energy usage cost (or charge) of the grid changes (for example, changes depending on a time), if the grid is in the normal state, it may not be efficient (e.g., economically efficient) to use the power of the grid as the internal consumption power (or the load power).